A coupled metal-insulator and antiferromagnetic transition of α-(BETS)2FeCl4 under high-pressure and magnetic field [BETS = bis(ethylenedithio)tetraselenafulvalene]

Coupling of metal-insulator and antiferromagnetic transitions in the highly correlated organic conductor incorporating magnetic anions,λ−BETS2FeBrx

“…6 together with that of -BETS 2 FeCl 4 . 19 It is clear that the critical magnetic field required to induce the fieldrestored highly conducting state becomes large with increasing x ͑or decreasing pressure͒. The H-T MI curve indicates that the 2 kbar state of -BETS 2 FeBr 0.7 Cl 3.3 is roughly equal to the zero-pressure state of -BETS 2 FeCl 4 .…”

“…7͑a͔͒. [18][19][20][21] The magnitude of the discontinuous drop of about 1.2ϫ10 Ϫ2 emu/mole(ϭ⌬M ) is more than 20 times larger than the paramagnetic susceptibility of -BETS 2 GaBr x Cl 4Ϫx . 12,26 The value of ⌬M corresponds to 7-8 % of whole magnetization (⌬M /M ϭ0.07-0.08) which is approximately equal to the ratio of the magnetization of the localized electrons (Sϭ 1 2 ) to that of the d electrons of Fe 3ϩ (Sϭ 5 2 ).…”

“…11,[18][19][20] Tokumoto et al have reported the magnetization of roughly oriented polycrystalline samples of -BETS 2 FeCl 4 and found the spin-flop transition around 1 T. 21 Magnetoresistance measurements by Goze et al showed that the MI transition temperature (T MI ) is reduced with increasing magnetic field and a field-restored highly conducting state ͑FRHCS͒ is observed above 10 T. 22 Pressure dependence of the resistivity under magnetic field also showed that T MI decreases when applying pressure and/or magnetic fields. 19 A detailed report on the magnetic properties and theoretical considerations on the MI transition of -BETS 2 FeCl 4 have been recently published. 20 Furthermore, we have recently observed a superconductor-to-insulator ͑SC-I͒ transition in the -BETS 2 Fe x Ga 1Ϫx Cl 4 (xϷ0.5) mixed anion salts where half of the anion sites are occupied by magnetic anions (FeCl 4 ).…”

The Electronic Structure and Spectroscopy of Metallo‐Dithiolene Complexes

“…Numerous metallo-dithiolenes have been synthesized and, depending on the choice of the transition metal and the nature of the dithiolene, possess lumophoric (249)(250)(251)(252)(253)(254)(255)(256)(257)(258)(259)(260)(261)(262)(263)(264)(265) magnetic (113,114,120,143,145,158,159,163,191,192,199,203,211,213,215,216,218,266,267), and conducting properties (111, 113, 121, 123, 124, 130-133, 136-138, 144, 155, 158, 159, 173, 175, 183, 185, 189-191, 193-195, 197, 198, 201-203, 205, 206, 217-219, 240, 241, 268-279). Perhaps the most fascinating function of transition metal dithiolenes is their ability to catalyze a variety of formal oxygen atom transfer (OAT) reactions in specific model systems and at the active sites of pyranopterin molybdenum and tungsten enzymes.…”

Novel Metallic State Carrying Localized Spins in the Molecular Conductor(DMET)2FeBr4

“…Moreover, the low dimensionality in their electronic structures caused by the inherent structural features of organic donors brings about various types of instabilities connected with their novel electronic states such as charge density wave, spin density wave, superconductivity, Wigner lattice, spin Peierls state, etc. The introduction of d electrons having localized magnetic moments into organic conductors adds another interesting aspect to these low-D electronic systems [2][3][4][5][6]. In a metallic organic conductor, p-electron carriers interact with the localized spins of the d electrons, as in the case of ordinary transition metals where the s-d interaction dominates the electronic and magnetic properties.…”